Scholarlink

<p>Natural zeolites, known for their remarkable cation exchange capacity, can be used as effective minerals for sequestering cesium released from contaminated water and soil resulting from nuclear accidents. However, it is necessary to immobilize cesium after exchange to prevent dispersion. Structural modifications of these zeolites, particularly through thermal treatment, are emerging as a viable approach to effectively immobilize cesium. These modifications also offer insights into mineralogical and structural changes under significant radiation exposure, thereby serving as potential back-fill materials in nuclear waste repositories. This investigation focuses on the encapsulation of cesium by stilibite and heulandite, using XRD and thermal analyses and a leaching test after heat treatment over 500&#xa0;°C after ion exchange of cesium. Cesium leaching experiments revealed variations dependent on the heat treatment temperature. Heulandite showed lower cesium leaching compared to stilbite at high temperatures, attributed to distinct dehydration characteristics and structural transformations at elevated temperatures, potentially correlated with different Si/Al ratios of the two zeolites. Both zeolites manifested decreased cesium leaching with increasing temperature of heat treatment, albeit exhibiting temperature ranges (700–800&#xa0;°C) wherein cesium leaching initially increased before decreasing again, likely due to phase transformations. At temperatures over 1000&#xa0;°C, both zeolites exhibited nearly negligible leaching, primarily attributable to the transformation of stilbite and heulandite into dehydrated zeolite CAS (Cs-aluminosilicate) and glass phases, respectively. This study highlights the dual capabilities of stilbite and heulandite as effective cesium ion exchange minerals and high-temperature encapsulants. Despite undergoing different phase transformations, these zeolites demonstrate significant potential as candidates for remediating radioactive cesium and as barrier materials in nuclear waste repositories.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

High temperature phase transformation of natural zeolites for cesium sequestration: insight into stilbite and heulandite

  • 期刊论文

  • 发表日期：

    2025年1月24日

查看全文
  • Seongyeop Kim,
  • Yeongkyoo Kim,
  • Eungyu Park

摘要

Natural zeolites, known for their remarkable cation exchange capacity, can be used as effective minerals for sequestering cesium released from contaminated water and soil resulting from nuclear accidents. However, it is necessary to immobilize cesium after exchange to prevent dispersion. Structural modifications of these zeolites, particularly through thermal treatment, are emerging as a viable approach to effectively immobilize cesium. These modifications also offer insights into mineralogical and structural changes under significant radiation exposure, thereby serving as potential back-fill materials in nuclear waste repositories. This investigation focuses on the encapsulation of cesium by stilibite and heulandite, using XRD and thermal analyses and a leaching test after heat treatment over 500 °C after ion exchange of cesium. Cesium leaching experiments revealed variations dependent on the heat treatment temperature. Heulandite showed lower cesium leaching compared to stilbite at high temperatures, attributed to distinct dehydration characteristics and structural transformations at elevated temperatures, potentially correlated with different Si/Al ratios of the two zeolites. Both zeolites manifested decreased cesium leaching with increasing temperature of heat treatment, albeit exhibiting temperature ranges (700–800 °C) wherein cesium leaching initially increased before decreasing again, likely due to phase transformations. At temperatures over 1000 °C, both zeolites exhibited nearly negligible leaching, primarily attributable to the transformation of stilbite and heulandite into dehydrated zeolite CAS (Cs-aluminosilicate) and glass phases, respectively. This study highlights the dual capabilities of stilbite and heulandite as effective cesium ion exchange minerals and high-temperature encapsulants. Despite undergoing different phase transformations, these zeolites demonstrate significant potential as candidates for remediating radioactive cesium and as barrier materials in nuclear waste repositories.